I think you should adjust your goal for NATs: don't lowball!
Before my first comp I was averaging 40, but ended up with a 38 avg. Yes, nerves add time, but when you're at a comp you're so in the zone that it compensates.
I first got mine in September, and solved it in December (after having to restart 3 times because of pops).
After a while I just resorted to excessive amounts of R U R' U', and by excessive I mean repeating it 20x to move 3 pieces